c
c friendship graph F_5
c every cycle can contain one blue vertex
c one cycle must contain a green vertex
c all others can be colored red
c F_x = x blue vertices
c
p edge 11 15
e 1 2
e 1 3
e 1 4
e 1 5
e 1 6
e 1 7
e 1 8
e 1 9
e 1 10
e 1 11
e 2 3
e 4 5
e 6 7
e 8 9
e 10 11

